﻿    <p>
      An <em>IfcGeographicElementType</em> is used to define an
      element specification of a geographic element (i.e. the
      specific product information, that is common to all
      occurrences of that product type). Geographic element types
      include for different types of element that may be used to
      represent information within a geographical landscape
      external to a building. Within the world of geographic
      information they are referred to generally as 'features'.
      <em>IfcGeographicElementType</em>'s include:
    </p>
    <ul>
      <li>point features such as seating, bus shelters, signage, trees;
      </li>
      <li>linear features such as layby's;
      </li>
      <li>area features such as ponds, lakes, woods and forests;
      </li>
      <li>drainage such as catchment, reserver or outfall.</li>
    </ul>
    <p>
      The specification of the specific types are given by the
      inherited attribute <em>IfcElementType.ElementType</em> given
      as an <em>IfcLabel</em>.
    </p>
    <p>
      Geographic element types are frequently identified in feature
      catalogs that are produced for particular purposes. The
      <em>IfcGeographicElementType</em> entity enables the continued
      use of existing feature catalogs through capture of their
      identity and attributes.
    </p>
    <p>
      Information from feature catalogs might be captured in
      various ways:
    </p>
    <ul>
      <li>via property sets, some of which will be specifically
      defined within the IFC property set catalog whilst others
      will be created for local use; this is the form of capture
      that is expected to be most widely used
      </li>
      <li>through use of the IFC classification model whereby
      features might be identified through an
      <em>IfcClassificationReference</em> with additional
      description; in which case, any further attributes required
      would still need to be captured in property sets.
      </li>
    </ul>
    <blockquote class="note">
      NOTE&nbsp; This is due to the range of choices of element type
      thyat are available and their expression in different
      languages. It is not considered possible to create a
      reasonably full list of types within an enumeration. It is
      suggested that selection of the relevant type be drawn from
      an available 'feature catalog'.
    </blockquote>
    <blockquote class="history">
      HISTORY&nbsp; New entity in IFC4.
    </blockquote>

